1. Field of the Invention
The present invention relates to a wireless transmission apparatus, and more particularly to a wireless transmission apparatus for transmitting a RF signal in a power allocation corresponding to specific transmission standard.
2. Description of the Prior Art
The wireless terminal apparatus in the prior art, e.g. the GSM mobile station, transmits a RF signal in a specific power allocation corresponding to the requirement of wireless transmission standard, e.g. the GSM specifications, by a wireless transmission apparatus. Like the GSM, the power allocation gradually ramp the power strength from zero to the needed level, and then the power strength is held steadily. Subsequently, the power allocation gradually ramps the power strength down to 0. The method to allocate the power strength transmitted is determined by a plurality of predetermined power ramp profiles. Besides, the power allocation may change the level of power and the allocation of the power strength transmitted according to transmission conditions, for example, the ambient temperature, the voltage of a battery, and the transmission frequency.
There are two methods to transmit the power of the wireless transmission apparatus in the prior art. One is according to different transmission conditions, to store all power ramp profiles in memories of the wireless transmission apparatus in advance. However, this method needs a lot of memories and is unbeneficial to the wireless terminal apparatus.
The other method, such as U.S. Pat. No. 5,159,283, is to store only a plurality of standard power ramp profiles in memories in advance. In practical application, choose a proper power ramp profile. A processor of the wireless transmission apparatus calculates and amplifies to an appropriate power allocation, and then transmits it. The processor may be a microprocessor, a digital signal processor, etc. This method uses fewer memories but increases a lot of load to the processor and cause that the wireless transmission apparatus must adopt a higher calculation speed and more expensive processors.
Other related arts further include U.S. Pat. No. 5,697,073, Europe patent No. EP 0407135A2, etc. The disclosed techniques within these patents all have the above disadvantages.
Thus, the primary objective of the present invention is to provide a wireless transmission apparatus for solving the above problems of occupying memories and the load of processors.